Continuous method of treating glyceride oils



United States Patent @fiice CONTINUOUS METHOD OF TREATING GLYCERIDE OILS George Bar-sky, New York, N. Y., assignor to E. F. Drew & Co., Inc., New York, N. Y., a corporation of Delaware Application November 23, 1954, Serial No. 470,713

7 Claims. (Cl. 260410.7)

The present invention is directed to esterification of fatty acids with polyalcohols and more particularly it is concerned with the treatment of glyceride oils of the coconut type, whereby the lower fatty acids thereof are displaced by higher fatty acids.

In applicants Patent No. 2,182,332, dated December 5, 1939, entitled Method of Reconstructing Glyceride Oils, there is described and claimed a process whereby a coconut type oil is mixed with a higher fatty acid and the mixture heated to a sufficient extent to free and vaporize the lower fatty acids, while at the same time the higher fatty acids are combined with the glycerine whereby the melting point of the oil is increased. This process has been successfully used in the production of hard butters but it is desirable to improve the process in various respects. As described, the process was a batch procedure so that a relatively long time was required in order to obtain the product. Also, it required very close supervision of each batch so as to produce hard butters which had the same characteristics in batch after batch. It was also difiicult to obtain the desired amount of reconstruction or displacement of lower fatty acids and to obtain such a result required a close control of the operation.

The present invention is intended and adapted to overcome the difiiculties and disadvantages inherent in the prior art and to provide a method of esterification of fatty acids with polyhydric alcohols which is continuous and in which the desired conditions are readily maintained.

It is also among the objects of the present invention to provide a process which is economical in the use of heat in the operation, which produces a better product, requiring a minimum of refining and with the elimination of auxiliary steps.

It is further among the objects of the present invention to provide an apparatus for the continuous esterification and displacement, which is compacbwhich is practically automatic in operation, requiring a minimum of supervision and resulting in the production of products having uniform and predetermined characteristics.

In practicing the present invention, there is provided a mixture of a glyceride oil and a fatty acid which are caused to react to produce certain esters. Specifically the coconut type of oil is used in one embodiment of the invention and the higher fatty acids having from 12 to 18 carbon atoms are mixed therewith. It is an important feature of the invention to use a relatively large excess of the higher fatty acid in order to facilitate the reconstruc tion reaction. The product containing a large amount of free fatty acid is removed from the reaction vessel and is heated under such conditions as to vaporize the free fatty acid. The incoming oil to be treated is caused to absorb the vapors of the free fatty acid whereby the desired mixture for reaction is obtained. The product, which is quite low in free fatty acid, is passed through a heat exchanger and the in-coming oil to be treated is also passed through the heat exchanger, being preheated thereby before passing into a vessel for absorption of the vapors obtained in the deacidification of the product.

, Thereby a continuous flow of all of the constituents is' In the accompanying drawing constituting a part hereof and in which like reference characters indicate like parts,

The single figure is a diagrammatic view of an apparatus adapted for the practice of the present invention.

The oil to be treated, which may be coconut oil, is introduced through pipe 1, passing through heat exchanger 2 and flowing through pipe 3 and having an extension 5 connected to a distributor 6 in the top of deacidification column 7. At the lower end of the column is a conical bracket 8 having a cap 9 on the upper side thereof so as to hold filling material 10, over which the oil from spray 6 is adapted to trickle down. A pipe 11 leads through pump 12 and pipe 13 into the center 14 of a bubble cap column 15.

The lower portion of the column is provided with a.

series of plates 16 with heating coils 17 on each of the plates. Bubble caps 18 are provided and pipes 19 lead from one section to the next lower section so as to allow the continuous flow of liquid down through the column. A heating coil 20 is provided in the bottom thereof and an exit pipe 21 therefrom extends to deacidification chamber 22 with a valve 21' interposed in pipe 21 for control of the flow. A steam coil 23 is provided in the bottom of chamber 22 and side chamber 24. Exit pipe 25 leads to heat exchanger 2 and the product flows from the system through pipe 26.

The upper portion 27 of column 15 is provided with a series of plates 28 having bubble caps 29 and pipes 30 to cause a flow of liquid successively to the various sections of the rectifying portion of the column. A pipe 31 from the top of the column leads to condenser 32, which is connected to receiver 33 connected to a source of vacuum 34. An exit pipe 35 from reservoir 33 is intended for the removal of condensed vapors from rectifying section 27. A pipe 36 extending from the bottom of receiver 33 and controlled by valve 37, enters the top of rectifying section 27.

From the top of deacidification column 7, a pipe 37' extends to condenser 38, which is connected to receiver 39. A source of vacuum 40 is connected to said receiver.

An exit pipe 41 is adapted to facilitate the removal of condensate from receiver 39. Generally the vacuum maintained in deacidification column 7 is higher than that oil by displacement of the lower fatty acids therein having, 6, 8 and 10 carbon atoms by higher fatty acids having 12 to 18 carbon atoms. In the apparatus shown in the drawing a temperature of 530550 F. is maintained in reaction section 15 and a vacuum of about to mm.

pressure. The temperature in the deacidification column 7 is about the same as in the reaction section but a higher vacuum of about 5 mm. pressure or less is maintained therein.

Assuming that the operation has been proceeding with,

a mixture of about equal parts by weight of coconut oil and free higher fatty acids having a free fatty acid content of about to calculated as oleic, there is introduced into feed pipe 1 a mixture of coconut oil and said higher fatty acid in sufiicient amount to displace from about 70% to 95% of the lower fatty acids. The mixture passes through heat exchanger 2 where it is preheated by the outgoing product formed in the process. The oil-fatty acid mixture is then distributed at 6 into the top of deacidification column 7 meeting vapors of free higher fatty acids arising from the product as it flows to Patented June 24, 1958.

the heat exchanger '2 'from chamber 22. The vapors are absorbed and dissolved in the oil mixture which passes into central portion 14 of thebubble cap column through pipes 11 and 13. Any vapors which escape are condensed. at 38 and returned to the feed or otherwise used.

As the mixture 'fiows downwardly o'verthe plates or trays of the column 15 a relatively rapid reaction takes place due to the high temperature and the large excess of higher fatty acids present. "There is maintained a cir' culating load of higher fatty acid between the reaction zone and the deacidification zone, which serves to increase the rate of reaction and to drive the reaction further in the desired direction. The volume of liquid in reaction zone 15 and the rate of feed at pipe 1 is such that the time of retention of the reactants in the reaction zone is usually from 2 to 4 hours.

The vapors of the lower fatty acids liberated from the glyceride oil and carrying some higher fatty acids with them, rise and pass through rectifying section 27 of the column or tower where the higher fatty acids are condensed and returned to the reaction zone 15. The vapors then are condensed in condenser 32 and are removed from receiver 33 through pipe 35, consisting essentially of caproic, caprylic and capric acids. Some of this condensate is cycled back into section 27 in order to maintain the composition at the top' plate of said section at a free fatty acid value of about 160 to 170. The reaction product leaves the bottom of reaction zone 15 through pipe 21 and is drawn into chamber 22 by the higher vacuum maintained therein, the flow being controlled by valve 21, thereby preventing the lower pressure in't'ne deacidification column from drawing off all of the liquid from the bubble cap column and disturbing the conditions therein.

In chamber 22 deacidification occurs, sometimes with the use'of a small amount of blowing steam, thevapors of the free higher fatty acids rising into and through column 7. The deacidified product having a free fattyacid'c'ontent usually under 1% and more specifically of about 0.3%, flows out through pipe 25 and heat exchanger 2 and. out of the system. It has a saponification value of about 236, the value being considerably less than that of the coconut oil used. The incoming oil-fatty acid mixture through spray 6 absorbs the vapors and the cycle continues.

In' starting up the system, the incoming feed of oil and higher fatty acids contains a larger proportion of the'fatt'y acids than is necessary to displace the lower fatty acids in order to build up the relatively large proportion of the circulating higherfatty acids which results in. the efiiciency of the process. When the desired amount of circulating load has been built up in the system, the amount of the-fatty acidsin the incoming oil is reduced to that required to displace the lower fatty acids.

The coconut type oil used in the operation may be the crude oil but a purified oil is preferred. The slime may be removed from the oil by filtering with a suitable earth as is commonly practiced. In any case, it is quite desirable to remove color forming bodies before the reaction as such bodies on the application of heat cause undesirablediscoloration which is difficult to remove in the subsequent refining of the product. While a refined oil is desirable, it is not necessary to alkali refine the oil completely since the free fatty acids present are of value in the operation as they take part in the reactions and are automatically fractioned in the system. The oil used may be hydrogenated before entering the system or at the end of the operation; then if the free higher fatty acids used are substantially saturated, the hydrogenationstep may be omitted entirely in the preparation of the final hard butter or fat.

Numerous advantages are inherent in the present process. The time of reaction is reduced to a fraction of the time necessary in the prior batch process. The large amount of circulating load of higher fatty acid ac- Al. 7 complishes this and furthermore minimizes decomposition and discoloration. A uniform product is obtained and without the use of close control or supervision of the operation. Since the acidity of the product is lower, less refining with alkali is required. Because of the short time of reaction, the capacity of the apparatus is greatly increased over the batch process. Heat economy is good as T the heat which would otherwise be lost in the removal of l the large excess of higher fatty acid and in the final product, is recovered in the form of the preheated feed of oil and higher fatty acid.

Other operations involving esterification reactions are also contemplated within the invention. In continuous esterification, the vapors from deacidification column 7 may be used to preheat the incoming feed. In the rectifying zone 27, the polyhydric alcohol, such as glycerine, is condensed and flows back into the re- 7 action zone 15 while the water vapor passes out and is condensed in condenser 32. The problem of a two-phase system between fatty acid and glycerine, for example, which occurs at the beginnnig of the operation, is solved by causing part of the fatty acid vapors to react directly with the glycerine to form monoand di-glycerides which dissolve in the liquid fatty acids and are re-cycled. This may be accomplished by feeding glycerine into a central section of the direct condenser 7, the incoming feed into the top thereof and the fatty acid vapors into the lower part thereof.

Various changes may be made in the details of the process within the invention. The proportion of circulating fatty acid may be varied substantially. Other oils may be similarly treated by the displacement process, such as palm kernal, babassu and the like oils. More than four sections may be used in the reaction section of the column. In place of a bubble cap column for a reaction a series of chambers or kettles or equivalent apparatus may be used that will give continuous flow with a minimum of intermingling of material in the various steps of the reaction. Instead. of condensing the freed lower fatty acids together, the vapors thereof may be fractionally condensed. The number of plates'in the rectifying section of the column may be varied, but from 6 to 12 such plates is satisfactory in operation. In place of the bubble cap plates of the rectifying section, the column may be packed with Raschig ringsor other filling material. All metal coming in contact with liquid or vapors of fatty acid should be acid resistant, such as 3116 steel. For heating purposes in place of high pressure steam, at high boiling liquid such as diphenyl or Dow- Therm, or electric heating, may be used.

These and other changes in the details of the process may be made without departing from the principles herein set forth and the invention is, therefore, to be broad-1y construed and to be limited only by the character of the claims appended hereto.

I claim: a

1. A continuous method of treating glyceride oils of i the coconut type to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifying such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, passing said reacted oil through a deacidification zone, heating said cleacidification zone to vaporize'free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle.

2. A continuous method of treating glyceride oils of the coconut type to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifying such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, passing said reacted oil through a deacidification zone, heating said deacidification zone to vaporize free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle, and maintaining a vacuum during said reaction, rectification and deacidification.

3. A continuous method of treating glyceride oils of the coconut type to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifying such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, passing said reacted oil through a deacidification zone, heating said deacidification zone to vaporize free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle, and maintaining a vacuum during said reaction, rectification and deacidification, the vacuum in the deacidification being higher than the vacuum in the reaction and rectification.

4. A continuous method of treating glyceriode oils of the coconut type to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifying such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, separately condensing said lower fatty acid vapors and returning part of said lower fatty acids into the rectification, passing said reacted oil through a deacidification zone, heating said deacidification zone to vaporize free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle.

5. A continuous method of treating glyceride oils of the coconut type to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifying such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, passing said reacted oil through a deacidification zone, heating said deacidification zone to vaporize free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle, and maintaining a vacuum during said reaction, rectification and deacidification, the temperature of deacidificationbeing higher than that of reaction.

6. A continuous method of treating glyceride oils of the coconut type to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifying such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, passing said reacted oil through a deacidification zone, heating s'aid deacidification zone to vat-porize free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle, said reaction zone being so arranged that said reaction mixture passes successively through sections of said zone.

7. A continuous method of treating glyceride oils to alter the characteristics thereof which comprises passing a mixture of said oil and higher fatty acid through a reaction zone, heating said zone to cause a reaction to take place releasing lower fatty acids in the vapor state, rectifyin such vapors in a separate zone to condense said higher fatty acid and return them to said reaction zone, passing said reacted oil-through a deacidification zone, heating said deacidification zone to vaporize free higher fatty acid from said reacted oil, introducing fresh oil into the path of said higher fatty acid vapors to absorb said vapors in said deacidification zone, passing the mixture of said fresh oil and higher fatty acid to said reaction zone for treatment in a cycle.

References Cited in the file of this patent UNITED STATES PATENTS 2,182,332 Barsky Dec. 5, 1939 2,378,006 Eckerf June 12, 1945 2,418,898 Murphy et al. Apr. 15, 1947 2,585,027 Mueller Feb. 12, 1952 

7. A CONTINUOUS METHOD OF TREATING GLYCERIDE OILS TO ALTER THE CHARACTERISTICS THEREOF WHICH COMPRISES PASSING A MIXTURE OF SAID OIL AND HIGHER FATTY ACID THROUGH A REACTION ZONE, HEATING SAID ZONE TO CAUSE A REACTION TO TAKE PLACE RELEASING LOWER FATTY ACIDS IN THE VAPOR STATE, RECTIFYING SUCH VAPORS IN SEPARATE ZONE RO CONDENSE SAID HIGHER FATTY ACID AND RETURN THEM TO SAID REACTION ZONE, PASSING SAID REACTED OIL THROUGH A DEACIDIFICATION ZONE, HEATING SAID DEACIDIFICATION ZONE TO VAPORIZE FREE HIGHER FATTY ACID FROM SAID REACTED OIL, INTRODUCING FRESH OIL INTO THE PATH OF SAID HIGHER FATTY ACID VAPORS TO ABSORB SAID VAPORS IN SAID DEACIDIFICATION ZONE, PASSING THE MIXTURE OF SAID FRESH OIL AND HIGHER FATTY ACID TO SAID REACTION ZONE FOR TREATMENT IN A CYCLE. 